Switch tracks, used to transfer train direction from one track to another, depend on precision joints within the switch that move and transfer movement of a train to another track. In winter months, snow and ice may build up within the joints preventing the drive motors or linkages from being able to shift position. This problem is typically solved by heating the rails to melt the snow and thus clear the obstacle.
As one of these heating systems, small smudge pots were used to provide open flame heating to sections of the rails. They are oil-filled and lit by hand much like an oil lamp using a wick to draw up the fuel to the top of the unit.
Next, open flame gas was used to deliver gas along the 30-foot section of rail that needs to be heated. As open flame is somewhat dangerous, and expending vast amount of gas was expensive, the rail roads moved to new sources of heating the rails.
Another common type of switch heater used is an electric resistive heating element that is attached along the rail for the 30 feet of the switch. Within a single switch, you would have two 30-foot long elements pulling 300 watts per foot at 480-volt alternating current (VAC) using 90 amps per phase. Also needed in this system are several smaller heating resistive units called crib heaters which add to the total load of the system. This system depends on thermal transfer from the outer element across an air gap and into the rail.
Hot air blowers are also used to heat railroad tracks. When used, these units use a blower to push air into a duct system and deliver air to the rail bed. The air is heated by means of either gas fired burners of passing the air over electric restive elements. The combined amperage of the blower motor and the heat source makes these units the most expensive units to operate in the field.
The present invention intends to address the aforementioned issues. In doing so, the present invention uses a magnetic inductive heating coil to introduce heat directly into the core of the rail with reduced levels of electrical energy needed to create higher levels of heat into the rail. Lab Test using 120 VAC has used as little as 5 amps to heat the rail to 220 degrees well above the 98 degrees needed. Also of note, all of the above systems need to be removed from the rails when routine track maintenance is conducted as the equipment used will damage the parts if left in place. This will not be the case with the new inductive heating heads. These small rugged coils of the present invention will be affixed to the rail in a manner that the rail maintenance equipment will not effect as the equipment passes over the area they are installed. By having multiple standalone heads, should one fail, the others will continue to operate unlike the Calrod system. In contrast, when one of the Calrod elements burn out or fail, the entire 30-foot section fails; thus shutting down the switch for rail traffic.
The inductive heads can be attached on the side of the rail or the underside of the rail. Lab testing has shown how rapid the rail is heated, given several power level settings on the equipment. The coils within each of the heads may be potted to ensure it will remain waterproof and vibration resistant.
The Inductive Heating System of the present invention will comprise multiple heating heads (depending on the size of the rail road switch) wired back to a central control panel located beside the tracks. Within the control cabinet will be the electrical power fusing, control relays, GFI protection unit, snow-detectors, thermostat, and a small PLC unit to allow for system operational programming.
The technology introduced through the present invention can produce 1800 watts at 120V single phase directly into an eleven-inch section of the rail with zero heat loss. This means that the heads will be placed at various intervals along the section of rail that needs to be heated. As the heat is created from within the rail, it will migrate down between the individual heads to create uniform heating above the 98 degrees needed.
The magnetic induction technology was first developed in the 1980's but is now available in a size that is usable for Rail Heaters. The heating heads would be quickly install to the rail by means of a clamping device, installed between the rail ties.
The present invention functions through a variety of controls. The control unit shall be housed in a free standing stainless-steel weather proof enclosure of sufficient size as to accommodate: 1. Power disconnects, fusing and voltage filter; 2. Power supply section with outs for up to 30 field induction heads. This can be accomplished in two versions, a single large power I generator or a rack of individual cards, one for each head. The overall system pricing can be held low with the use of “Off the Self’ control cards that are now being produced for magnetic induction cooking hotplates; 3. A small PLC shall be installed to govern the system total performance in the field. This unit will issue instructions to the control cards and power supply to control the amperage sent to the induction heads. This will allow for the optimum electrical power saving given weather and or train conditions; 4. Rail temperature sending units shall supply the PLC with data regarding rail overall temperature; 5. An external thermal temperature sensing unit will supply the PLC the ambient temperature so that the system will know when freezing conditions are present; 6. Two external snow detection units shall be used to detect when snow is present. One located above the control cabinet and one at the track bed to detect when snow or ice is dropped by passing trains; 7. A GFI device will be installed to ensure that any field short is detected for safety shutdown reasons; 8. An internal cabinet ambient temperature control unit shall be installed to keep the control components at designed performance levels in below freezing weather events; 9. System contactors, relays, and drivers shall be used for induction head control.
When considering the programming unit of the present invention, the PLC unit will activate the induction heads and power the total array creating heat within the rails until the system track temperature set point (adjustable) is reached. At this point, the heads will shut off and the rail temperature will begin to drop through a dead band (adjustable) until the lower temperature threshold point is reached. The PLC will then repower the induction head and take it to the rail temperature set point again. This process will continue as long as the snow detectors are indicating snow is present. An optional time window for heating the rail after the snow detectors have dropped out will be available to ensure the track bed is free of snow and ice. In this manner, the overall system heads will pulse on and off to reduce the total system electrical amperage to the lowest level possible.
Should the PLC detect that a passing train over the induction heads has drastically reduced the rail temperature by means of the air turbulence generated by the train or the snow and ice dropped; the unit will respond by raising the wattage delivered to each head of a short time to restore the rail temperature set point. In this way the unit is self-adjusting to not only control the total system amperage, but also ensure the track bed and switch are ready for the next train.
The overall system control system shall have the capability to be viewed from a remote location via a cellular modem connection to the internet. This interface shall allow for the monitoring of the equipment, system diagnostics, and or changing the system programming from that remote point.
The wiring of the individual heads shall be accomplished by means of flexible armored cables fitted with quick disconnects that attach to two parallel conduit arrays that lay to the side of the rails in the ballast stone. There shall be a small junction box for each side of the typical railroad switch. From the junction box, the wires will pass into a wire tray and on to the induction coils. A wire tray will be designed to be a rigged device so that the wire tray can be separated if components need to be replaced. Since heat is not transferred from the induction head to the rail, the safety of railroad personnel is guaranteed. Unlike existing system now used in the Rail Road Industry, the induction heads will not be required to be removed from the rails and then put back in place when a Track Tamper Machine passes over the switch for normal track maintenance.
The induction heads shall be attached to the rail by means of a quick connection rail clamping unit. The clamp will require no changes to the rail in the field and shall allow the head to be moved to multiple locations in the switch bed to accommodate variances in track layout. The heads can be used on the outer body of the main rails or can be placed at the “Moving Switch Point” to maximize overall system efficiency. The body of the head shall be constructed of fiberglass with the induction coil potted in a non-conductive binder to ensure that track and train vibrations do not affect the performance. The potting of the coil will also make the head water proof and form an insulation barrier to guard against electrical shorting in the field wiring.
The “crib” area is referred to as the area between the ties that the linkage arms are located that attach to the Switch Motor that move the rails in the switch. Should this area become impacted with snow and ice the linkage arms are prevented from movement and the switch is disabled. This area can be heated by use of an induction head attached to a steel plate that covers the area. Again, all the same features and control benefits of the main induction heads are relative to this section of the system.
This program has been mandated by the Federal Government to track train movements across all railroads in real time. To accomplish this, Railroad Signal Systems use “Track Circuits” and inject low level voltage into the track that is not allowed to be affected by other systems or hardware. As each of the induction heads are insulated from the rail by means of its insulated wire and disconnect plug, the system will not allow for conductive shorting of the rails. The heating systems that are now used in the industry often provide ground paths through the metal parts and or cables which defeat “track circuits” used in modern “Positive Train Control signaled territory”.
On all Rail Road Bridges across the industry, Lift Rail Joints are required for the parting of the rails when the bridge is opened. During winter months, snow and ice fall into the pockets when the bridge is opened. As the bridge is closed back up if this snow and ice prevents the rail from reseating, rail traffic is held up until the pockets can be cleaned out and the rails reseated. By clamping the small induction head to the pocket plate steel on the bridge, the pockets can now he heated in the same manner as rail switches and the pockets will be self-cleaning at the site.
In order to function, low frequency “E” heads require a large mass of steel configured into what is typically shaped like the letter E. It is necessary to construct these units out of a large mass of steel (up to eight inches thick) due to the low power needed to establish enough thermal heat to be effective for melting snow and ice in the track bed. In order to accommodate the bulk of the E Head, large amounts of ballast stone are needed to be removed from between the track ties to fit the heads into place. As track maintenance machines called “Tampers” run over the area where the heads are located, the tamper will dump ballast stone back into the area where the heads are located. Should a heavy fright trail pass over the heads, the weight of the trains will press down on the rail/E head and is likely to damage the unit between the rail and the stone. Also, the bulk of the E Heads will not lend it to be mounted on the side of the rails in switching areas. For this reason, this technology has not been used in heavy freight traffic lines in the USA.
The E Heads are used on light commuter lines in Europe as long as it is understood that additional effort is undertaken to keep the ballast stone removed from under the heads. For these reasons the small, thin profile of the powerful magnetic inductive coils described in this Patent offer superior performance and flexibility to the rail industry.